Electropneumatic brake



zot-35,106

Sept. 22, 1936. E. E. HEwlTT ELEGTROPNEUMATIC BRAKE Filed O Ct. 1'0, 1934 ORN - INVENTOR` N ELLIS EHEwn-T- Patented Sept. 22, 1936 ELECTROPNEUMATIC BRAKE Ellis E. Hewitt, Edgewood, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application October 101934, Serial No. 747,729

17 Claims.

This invention relates to electropneumatic brakes, and more particularly to electropneumatic brakes for high speed trains.

In trains designed for high speed service safety A considerations demand that the braking equipment employed provide for the highest practical degree of reliability. One manner of providing for this reliability in a fluid pressure brake system is to arrange the system such that an application of the brakes may be effected either by straight air operation, by automatic operation, or by a combination of the two. In systems of this character a control valve device is generally l provided on each car in the train, and these valve 1'5 devices are controlled from the head end of the train through some form of controlling brake valve device.

Each control valve device most generally comprises some form of relay valve for controlling all 20 controlled valve device and an automatic valve device for controlling operation of the relay valve. The electrically controlled valve device controls operation of the relay valve during straight air operation, while the automatic valve devicecontrols operation of the relay valve during automatic operation. In addition to these valve devices, the control valve device usuallyincludes additional electrically actuated valvesA under the valves-and retardation controller device function to control the brake cylinder pressure so as to decelerate the train at some predetermined desired rate of retardation. The retardation controller device and electrically actuated valves usually function to first cut off the supply of fluid under pressure to the brake cylinder and subsequently to effect a release of fluid under pressure from the brake cylinder. One of the difficulties heretofore encountered has been that more fluid under pressure has been released from the brake cylinder through this operation than necessary to maintain the desired rate of retardation, with the result that the rate maintained was not Vmain- 45` tained constant within tolerable limits. In addition, there has been an undesired cycling operation of the apparatus in alternately supplying fluid under pressure to and releasing it from the brake cylinder, thereby causing unnecessary loss of fluid pressure. It is desirable in practice that the retardation controller device function first to cutoff the supply of fluid under pressure to the brake cylinder, and thereafter, as the speed of the train diminishes and the coecientof friction between the rubbingparts of the brakes increases,

flow to the brake cylinder, and an electrically control of a retardation controller device, which to intermittently release fluid under pressure from the brake cylinder without at any time re- Vsupplying fluid under pressure thereto.

However, while it is desired that the retardation controller device release from the brake cyl- -1 inder whatever fluid under pressure is necessary to maintain the desired rate of retardation, an accidental release of total brake cylinder pressure should be guarded against.

In the equipments providing for both straight air and automatic operation as heretofore proposed, the retardation controller device has been effective in controlling only applications effected by straight air operation. It is of course desirable that the retardation controller device be effective in controlling applications by either straight air operation or by automatic operation.

With the above considerations in mind, it is a principal object of the present invention to provide a brake equipment in which applicationsmay be effected either by straight air operation or by automatic operation, and in which a retardation controller device may be employed to control applications by either mode of operation.

Another object of the present invention is to provide means for effecting a more gradual release of the brakes in response to operation of the retardation controller device, so as to prevent the needless loss of uid under pressure and to maintain a more nearly constant rate of retardation.

A yet further object of the invention is to provide means, in connection with an equipment of this character, which will prevent a total loss of brake cylinder pressure in the event of undesired operation of the electrically actuated valves controlled by the retardation controller device.

Yet further and more specic objects of the invention will appear from the following description, which is taken in connection with the single figure of the attached drawing, which shows in schematic and diagrammatic form one arrangement of apparatus which may be employed in carrying out the invention.

cated on each car in the train.

At the head end of the train, I provide a controlling brake valve device, diagrammatically indicated at I4, and this brake valve device is employed to control operation of all of the control valve devices throughout Vthe train.

In order to limit the rate of retardation produced by an application of the brakes to some predetermined maximum value which will not produce sliding of the wheels, a retardation controller device I6 has been included, and this device functions to control certain electrically operated valve devices, as will more fully appear hereinafter. f Y

Considering now more in detail the control valve device I8, this valve` device comprises a relay valve section I8, an electrically controlled self-lapping magnet valve section 28, an auto-V matic valve section 22, a pneumatic cut-off vvalve section 24, an inshot Valve section 26, and a magnet valve section 28.

The Vrelay valve section I8 controls the supply offluid under pressure from a connected supply reservoir 38 to the connected brake cylinder I2. The-flow ,ofV fluid from the reservoir to the brake cylinder is V controlled by a supply valve 32, which is disposed in a valve chamber 33. The valve 32 iis-urged toward a seat 34 by 'a spring 35. Disposed within'the supply valve 32 is a pilot valve 36, urged toward a seat 31 by a spring 36.

When the pilot valve 36 is seated, the uid pressure acting upon the valve 32 from the valve chamber 33, plus the pressure of spring 35, will -hold the valve upon its seatV 34. When the pilot valve 36 is actuated to unseated'position, fluid under pressure in the valve chamber 33 is released past'the unseated pilot valve to a slide valve chamber 48 at a rate fasterV than it can be vsupplied Vto the valvechamber 33 through a choke 39 from'a'. supply chamber 4I, which is inV communication with the supply reservoir 38 by way of passage 42 and pipe 43. As a consequence, the pressure on the upper side of the valveV 32 is reduced and the'valve can then be unseated by a relatively small pressure from below. When the valve 32 is unseated, .fluid under pressure may iiow fromr the supply chamber 4I, and the supply reservoir `38, to the slide valve chamber 48.

Disposed in the slide valve chamber 48 is a slide valve 44, and for operating the slide valve and for unseating the pilot valve 36 and the main supply valve 32, there is provided a piston 45 disposed'in a pistonl chamber 46 and having a stem 41. The piston stem 41 is provided with an enlarged flanged portion 48 interfitting with a bore Y49, for the purpose of providing a seal between `the piston' chamber-46 and the slide valve chamber 48 as the piston 45 moves. Also, the stem 41` is provided with a guiding element 58 for guiding movement of the stem when the piston 45 is moved upwardly and downwardly. The slide valve 44 is carried in a recess in the stern 41 and its movement is coextensive with the movement of the piston 45.

The slide valve chamberV 48 is in constant communication with the brake cylinder I 2 by way. of pipe and passage I and is also in restricted communicartion with the piston chamber 46 by Vway of passage 52, in which is disposed a choke 53.

-The slide valve 44 controls communication between the slide valvechamberV 48 vand the atmosphere, by way of passages 54 and pipe 55.

- In release position of the relay valve section I8, which is that shown in the drawing, the piston 45 is in its lowermostposition, where an annular flange thereon contacts andiseals with a corresponding annular portion of a gasket 56. In this position, the slide valve 44 uncovers one passage 54 and a port 51 therein registers with the other passage 54, so that fluid pressure may be released from the slide Valve chamber 48, and the connected brake cylinder I2, to the atmosphere by way of passages 54 and pipe 55.

When the relay piston 45 is actuated upwardly to application position, slide valve 44 blanks both of passages54, to cut oi communication from the slide valve chamber 48 and the brake cylinder I2 tothe atmosphere, and thereafter the upper end of the piston stem 41 first engages stem 58 of the pilot valve 36, to partially unload the main supply valve 32, and then engages and unseats the main supply valve. Unseating of this supply valve effects a supply of fluid under pressure to the slide valve chamber 48 and the brake cylinder I2, through the passages heretofore indicated.

Relay piston 45 is actuated to application position by the supply of fluid under pressure to the volume therebelow. When fluid under pressure is thus supplied below the piston it acts initially upon the piston area within the annular ange in engagement with the gasket 56, and as soon as the piston is lifted from the gasket, fluid pressure then acts upon the total piston area and thus causes the piston to move quickly upwardly to application position.

When the supply of fluid under pressure to the volume below the piston has been cut off, the pressure of fluid flowing to the space above the piston, through the choke 53, equalizes with that below, whereupon the piston moves downwardly until the supply valve 32 is seated. The supply of iiuid under pressure to the brake cylinder is then lapped.

The supp-ly of fluid under pressure to the volume below relay piston 45 is primarily controlled by the self-lapping magnet valve section 28 during straight air operation, or by the automatic valve section 22 during automatic operation, and secondarily by the inshot valve section 26 andthe cut-olf valve section 24 Yduring either operation.

The self-lapping magnet Vvalve section 28 is provided with a supply valve 68, which controls the flow of fluid under pressure from the supply reservoir 38 to the Volume below relay piston 45, by way of pipe 43, passages 42 and 6I, past supply valve 68 when unseated, to passage 62, and from thence through the inshot valve section and the pneumatic cut-off valve section, as will hereinafter be more fully described.

The supply valve 68 is urged toward seated position by a spring 63, and toward unseated position byl action of an electromagnet having a winding 64, which when energized actuates members to be described to unseat the valve. When the winding 64 is energized, the magnetic effect produced thereby actuates a movable core member 65 downwardly. Secured to the core member 65 is a stem 66 which engages a pin 61 to actuate a sliding` member 68. The sliding member 68 is provided with a valve seat 69 which engages and interts with the upper end of the stern of the supply valve 68, which end forms a release valve 18, controlling the vrelease of fluid pressure from the volume below relay piston 45.

'I'he sliding member 6,8 is normally held in an upper or release position by a resilient diaphragm 1I, which is secured thereto and to the casing embodying the self-lapping valve device in a manner tov form a chamber 12 therebelow and a `chamber 13 thereabove.A When the sliding member68 isinits upper or release positiom'the re'- lease valve16-is unseated,vso that uid pressure is released from the volume belowrelay piston 45 to the atmosphere, past the `unseated release valve, 4through an orifice 14, passage 15, and port 162 i v When the sliding member 68 is actuated downwardly theV release valve 16 is seated, to cut off this lcommunicationto the atmosphere, and the supply valve 66 is unseated,to eiect a supply of fluid under pressure to the under side of the relay piston. l l f The'downwar'dmovement of the sliding member 66V is,` as aforesaid, caused by downward movement of the core member 65. The downward movement of the core member 65 is opposed by a spring "18 reacting against a Vspring cup 19 secured to the upper end of stem 66. The

downwardfmov'ement of the core member 65 and the stem 66is governed or limited by aflanged collar '86,which is adapted to engage a stop Washer 8| upon a predetermined downward movement of the corel and stem.

As may be seen from the construction shown in the drawing, the spring cup 19 and the flanged collar 86 may be Aadjusted'to different positions on the stem 66. The stem 66 may be also adjusted with respect to the Acore member 65 by means of the screw-thread connection shown.

The lower end of the core member 65 is preferably of a bevelled configuration, as shown` in the drawing, and interts with a corresponding recessed portion ina stationary core member 82, so as to provide an air gap-therebetween of somewhat decreased reluctance. The casing embodying the `valve device provides the return path for the magnetic flux1established by the energized winding 64.

When the winding 64 is energized, the release valve'16 is rst seated and the supply valve 66 innext unseated anamount in accordance with the downward movement ofthe stem 66 and movablecore 65. This movement is opposed by the spring 18 and the unseatingof the supply valve 60A is thus determined by the degree of energization of the winding 64;

When the supply valve 66 is unseatedA uid under pressure also flows to the'chamber `12 below the diaphragm 1|, by way of passage 83, andi when the fluid pressure acting Vbelow the diaphragm overbalances that acting downwardly on the diaphragm due to the magnetic pull on the. core member65,l the sliding member 68 is actuatedupwardly to permitsupply valve 60 to beseated'by spring 63. ,The supplyY of iiuid under pressure tothe volume belowV relay piston 45 will then be lapped. ivIf the pressure below diaphragm 1| is great enough, release valve 16 may be unseated to release pressure from below the relay piston. If, on the other hand, after supply valve 66 is seated the pressure below the diaphragm should diminism, ,due to leakage or for other reasons, the diaphragm will be actuated downwardly'by the magnetic force above, to unseat ,the supply valve and thus readmit uid underfpressure to the volume 'below4 the` relay piston. VThe self-lapping magnet valve portion thus operates to supply and maintain a pressureto the relay valve'section inac'cordance with'the current supplied to the winding 64.` e

As before indicated, the supply of uid under pressure nto the volume below relay piston 45 may be also controlledby'the automatic valve section 221' This section is providedwith aslide valve chamber 85 in which is disposed a main slide valve 86 anda graduating valve 81. For operating themain and graduating valvesthere is provided a piston 88, disposed in a piston chamber 89.'V The piston 88 is provided with a stem 96 adapted to move the'graduating valve 81 coextensive therewith, and' to move" the main slide valve 86 with a delayed or lost motion.

The piston chamber 89 is in communication with a brake pipe 92 by way of pipe and passage 93. When the pressure in the brake pipe is normal, that is, maintained at a lpredetermined value, the piston, 88 is in its lowermost position, as shown inlthe drawing, which is also the release position. In this release position, a cavity 94 in the main slide valve 86 connects a passage 95', which leads tothe atmosphere by way of pipe 96, with a passage 91, which has two branches, one branch leading by way of pipe 98 to a volume reservoir 99, and the other branch leading by way of passage |66 to a double check valve chamber I in which is disposed a double check valve |02.

In release position, the main slide valve 86 also has a port |63 in registration with a passage |64 leading to a valve chamber |65, in which is disposed a fast recharge valve |66, urged toward a seated position bya spring |01. This fast recharge valve |06 controls communication between the passage |04 and the brake pipe passage 93, as will hereinafter be more fully referred to;

The slide valve chamber 85 is connected to an auxiliary reservoir ||0 by way of pipe and passage I; When the pressure in the piston chamber 891s reduced at a service rate, the overbalancing pressure beneath the piston in th-e slide valve chamber actuates theV piston upwardly to service position. In service position, the main slide valve 86 blanks the two passages 95 and |64, and brings port |2 therein in registration with the passage 91, the graduating valve 81- having uncovered the port 2 at this time. Fluid under pressure then flows from the main slidev valve chamber 85', and the auxiliary reservoir H6, to both the volume reservoir 99 and to the double check valve chamber |6|, according to the degree of reduction in brake pipe pressure.

The pressure of fluid supplied to the double check valve chamber |0|, above the double check valve |02, will actuate the double check valve to lower position, and thereafter fluid under pressure willflow to the volume below relay piston 45, through the inshot valve section, as will more fully appear presently.

When the pressure in piston chamber 89 is reduced at an emergency rate, th-e piston 88 moves upwardly andseals against gasket I I4, and the main slide valve 86 uncovers passage 91 while blanking passages 95 and |04. Fluid under pressure then ows from the slide valve chamber 85, and the auxiliary reservoir I0, to both the volume reservoir 99 and the volume below relay piston 45 until equalization takes place.

As before stated, uid under pressure supplied to the volume below relay piston 45 by operation of the self-lapping magnet valve section 20`also flows through the inshot valve section 26, nowing rst to the double check valve chamber |0|, Where the pressure of the fluid actuates the double checkV valve |02 to its upper position. From the double check valve chamber |0|, the ow is initially through two branches, one branch being by way of passage and the other branch being by way of aball valve chamber ||6 Disposed in this chamber is a ball valve ||1, which is urged toward an unseated position by action of. a spring -I I8 actingv upon a piston` II9 having a stem |20 lengagingthe ball valve. An adjusting member |2| is provided for adjusting the tension onthe spring I I8, and upward movement of the piston II9, and consequently the unseating of the ball valve II 1, maybe controlled by adjusting nuts |22 threadablyV disposed on an adjusting stem |23 associated with the piston.

When the ball valve I I1 is in unseated position, uid under Ypressure may iiow from the chamber |I6 past the unseated ball valve to a passage |24 leading to the volume below the relay pistoni45. Y

lare under the control of the retardation As the pressurel of the iiuid supplied to the volume below relay piston 45 increases and reaches a predetermined value, it acts upon the ,upper-sideof the inshotpiston II9 and actuates the piston downwardly against resistance of spring IIB, to seat the ball valve II1. After the ball valve is seated, the flow of fluid to the volume below relay piston'45 takes place only through the passage II5, which leads through the pneu- ,matic cut-olf valvesection 24.

The pneumatic cut-off valve section 24 is provided with a slide valve |25, disposedin a slide valve chamber |26, and a piston |21 disposed in a piston chamber |28. The piston |21 has a stem |29 adapted to actuate the slide valve |25 coexte'nsive with movement of the piston |21. A spring .|30 urges theA pistonV |21 upwardly to a vnormal or biased position.Y In this position a cavity I3| in the slide valve |25 connects the aforementioned passage II with a passage `|32 joiningrwith the passage I24-leading to the volume below relay piston 45.

, lAt the same time, al port |33 in the slide valve |2 5 is in registration with a passage |34 leading lto a control reservoir |35, so that the slide valve chamber I 26 is connected to this control reservoir. Theslide valvechamber |26 isV in con- -stant communication with the brake cylinder I2 by way of passages |31 and |38, and hence when the piston |21 is in its upper position, the control reservoir r|35 and brake cylinder I2 are connected.

The piston chamber |28 is at Vtimes* also in communication vwith the brake cylinder I2, through a passage-|39 which runs through the magnet valve section 28 to connect with the aforementionedrpassage y|31 leading to theV brake cylinder. When the pressure in the piston chamlberw|28 substantially equals the pressure in the slide valve chamber |26, the piston I 21 will remain in its upperposition. When the pressure in the piston chamber |28 is reduced below that in chamber |26, the overbalancing pressure in the chamber |26 actuates the piston downwardly to'where it engages gasket |40. In this position of the piston |21, the slide valve |25 blanks passage I|5 and connects passage |32 to passage |34, for a purpose which will appear later.

The pressure in the piston chamber .|28 is controlled by the magnet valve section 28. This valve section comprises a double beat valve |42, which controls the supply of fluid under pressure .to and its release from the aforementioned piston chamber |28, and a release valve |43, which controls the release of Viuid Ypressure from the volume below relay piston 45. These two valves controller device I6. Y

The double beat valve |42 is urged toward an Vtromagnet in the upper part of the casing, which whenV energized actuates the valve downwardly. When in upper seated position, the double beat valve |42 opens communication between the piston chamber |28 and the brake cylinder I2, and when in lower seated position this communication i's cut oif and the pressure in the piston chamber |28 is released to the atmosphere through an exhaust port and passage |45.

The releasevalve |43 is urged toward seated position by a spring |46 and toward unseated position b y action of another electromagnet in the upper part of the casing, which when energized actuates the valve downwardly. In unseated position, this valve opens a communication between a passage |41, leading to the volume below the relay piston 45, and a passage |48 leading to the seat of a limiting valve |49.

As shown, the limiting valve |49 is urged toward its seat by a spring |50, and is adapted to be actuated to unseated position by a chosen pressure in the passage |48. In unseated position, the valve |49 permits the release of fluid pressure from passage |48 and the volume below relay piston 45 to the atmosphere, by way of an exhaust passage |5I.

The brake valve device I4, which controls the major operations of the control valve device I0, may be one of a large number of types and in the type illustrated comprises a drum controller portion having a drum |54, adapted to engage and connect together a pair of contact fingers |55 and to thereafter sequentially engage a plurality of contact fingers |56, to electropneumatically control brake applications by. straight air operation.

'I'he brake valve device also includes a valve portion for effecting and controlling applications by automatic operation. This portion is preferably provided with a rotary valve diagrammatically shown at |51, which is adapted to control communication between a branch pipe |58, connecting with the brake pipe 92, and a feed valve pipe I 59,.and with an exhaust pipe I 60 leading to the atmosphere.

The feed valve pipe |59 connects with a feed valve device IGI, which in turn is connected to a source of fluid under pressure, as for example a main reservoir |62. The feed valve device I6| may be of one of a large number of types, and as is well known in the art, is provided for the purpose of maintaining a substantially uniform pressure of the fluid supplied from the main reservoir |62. Y

The drum controller and rotary valve portions are preferably combined in a manner such that bothmay be operated by manipulation of a single control element, as for example the familiar brake valve handle. This control element, or handle, is movable to diierent positions, as indicated inthe diagrammatic representation shown in the drawing, and as will hereinafter be referred to.

In order that the supply reservoirs 30 throughout the train shall be charged at all times, a supply pipe |6l| isY provided which extends throughout the train. Each of the supply reservoirs 30 is then connected to this pipe, so that the supply reservoirs are at all times charged to main reservoir pressure.

The retardation controller device I6 may also be of one of a large number of types and for that reason I have shown in more or less diagrammatic form a pendulum type which may be employed. In this type a pendulum |66 is freely suspended from a frictionless pivot |61 and carries therewith-andinsulatedtherefrom contacts |68 andr The retardation controller device ispositioned on the vehicle so that the pendulum |66 is swung to the right or left according to the rate of speed change of the vehicle. As the pendulum |66 swings to the left, its contact |68 will rst engage a stationary and resiliently supported contact |10, and thereafter another and similar stationary contact |1|. As the pendulum swings to the right, itengages in'a similar manner similar stationary contacts |12 and |13. Y

Considering -rst the contacts to the left, the contact |10 is connected to the electromagnet in the magnet valve section 28 controlling the double beat valve |42, and the contact |1| is connected to the electromagnet controlling the release valve |43. `The other terminalof each of these electromagnets -is connected to a ground `connection |14.A 'I'he movable contact |68 of the retardation controller device is connected to one terminal of a battery |15, andthe other terminal of the battery is also connected to a ground connection, so'that as the movable contact |68 engages the stationary contacts |10 and |1l| the electromagnets in the magnet valve section 28 will be energized. l

Now if when the train is decelerating the pendulum |66 swings to the left, it will be obvious that contacts |68 and |10 will be brought into engagement at one rate of retardation, and that contacts |68 and |1I will be brought into engagement at a higher rate of retardation. The double beat valve |42 will then be actuated downwardly when the iirst two of these. contacts engage, and the release valve |43 will be unseated when the second of these contacts engage. When it is desired that the same result be Yaccomplished for either direction of swing of the pendulum |66, then contact |12 is connected to Contact |10, contact |13 is connected to contact I1|, and contact |69 is connected to contact |68. Y

If howeverfit is desired that contacts |12 and |13 be employed in connection withcontrolling the acceleration of the train, then these contacts may be connected to an acceleration control apparatus, as described and claimed in the copending application of *Clyde C.i.larmer,` Serial No. 707,918, led January 23, 1934.V l

The operation of this embodiment of my invention is as follows:

v Running condition Y When the train is running, the brake valve device I4 at the head end of the train is maintained .in Release position, in which the `active parts of the brake vvalve device are in the position shown in the drawing.Y As will be observed, in thisposition the drum |54 isout of engagement with the contact fingers, and the rotary valve |51 connects the feed valve pipe |59 with the brake pipe branch pipe |58, by way of port The brake pipe pressure is thus maintained uniform by thev feed valve device |6|, and each auxiliary reservoir I is charged from the brake pipe 92 by Way of charging groove |11 in the automatic valve section 22. With the brake pipe pressure maintained at normal, each automatic Valve piston 88 will be in its lower position, as shown.

y At the same time, in each self-lapping magnet valve section 20, the supply valve 60 will be seated and the release valve 10 unseated, so that the Volume below the relay piston 45 `will be in communication with the atmosphere and.

the relay piston will be in its lowermost` Vor release position.

The other Vparts of the apparatus shown will be substantially in the positions indicated.

Service application lapping magnet valve winding 64, through a resistance |16. As the drum |54 rotates,it sequentially engages the contact lingers |56 to progressively out out portions of the, resistance |19, and thereby energize each winding .64 according tooperation of the brake valve devicethrough the. Electric service zone.

In each control valve device, with the winding 64 energized, the core member 65 is actuated downwardly to first effect seating of release valve and subsequently unseating of the supply valve 60. Fluid under pressure then iiows from the supply reservoir 30 to the volume below relay piston 45, through a communication including pipe 43, passages 42 and 6|, past the unseated supply Valve 60, passage 62,. double check valve chamber |0| (where double check Valve |02 is actuated to upper position), and from thence to the volume below relay piston 45 by way of two paths. The first of these two paths includes passage H5, slide valve cavity |3|, and passages |32 and |24. The second of these paths includes ball valvechamberA I6, past unseated ball valve ||1, and passage |24. Y

Fluid pressure beneath the relay piston 45 `actuates the piston and slide valve 44 upwardly to cut oi the communication between theslid'e valve chamber 40 and the atmosphere, and to effect unseating of the main supply valve 32. Fluid underpressure then ows from the Vsupply reservoir 30 to the slide valve chamber 40 and from thence to the brake cylinder |21 As the pressure on the under side of relay piston 45 builds up, a value will be reached at which the inshot piston ||9 .will be actuated downwardly far enough to seatthe ball valve ||1. Thereafter the ow of fluid to the under side of the relay` piston will be by way of the other path only. The pressure at which the ball valve ||1 closes is selected asthat corresponding to a brake cylinder pressurewhich will insure that the train will be brought to a stop in case the path leading through the cutoi valve section 24 should be closed. This brake cylinder pressure is preferablywell `below that generally obtaining in normal full service applications, in which the retardation controller device iseffective.

The supply of fluid under pressure to the relay valve section will be lapped by the self-lapping valve section when the pressure reaches a value corresponding to the brake valve movement, and when the supply thereto has been lapped, the relay piston 45 will move to lap position.

In the train, each self-lapping section 20. of

the train begins to decelerate. 10"

brake cylinder. I2, it also iiows to the piston chamber |28 in the pneumatic cut-oi valve section 24, by way of passage |31, past the unseated double beatvalve |42, and through passage |39, and to slide valve chamber I26, by way of passages |31 and |38.

jAs pressure builds up in the brake cylinders, If the rate of retardation produced by application of the brakes is suflicient to cause the pendulum |66, of the retardation controller device I6, to swing far enough to the left to causeV engagement of contact |68 with contact |10, Ythen each electromagnet controlling a double beat valve |42 Vwill be energized, and the double beat valve will be actuated to lower seated position, to cut oil communication between the Abrake cylinder I2 and the piston chamber |28 in each pneumatic into communication the volume below relay p-iston 45 andthe control reservoirV |35, The control Vreservoir |35 is lat this time' substantially at Vthe same pressure as the volume below relay. piston 45, because as fluid is supplied to the brake cylinder I2 it also ows to this reservoir, through passages |31 and |38, slide valve chamber |26, port |33, and pipe and passage |34.

Ifrnowthe rate of retardation is great enough tocau'se engagement of contact |68 with contact I1I, each Aelectromagnet controlling a 'release valve |43 will be energized, and the release valve `will be unseated. Unseating of this release valve releases iiuid under pressure from the volume below relay piston 45, and from the now connected control reservoir |35, to the atmosphere, through'passages |48 and |5|, the limiting valve |49 being unseated by the pressure in the passage |48. Y Since theY control reservoir |35 is connected to the Volume belowj the relay piston 45, the effect of this release of pressure upon the operation of the Vrelay valve section I8 is more gradual than were the vadditional volume of the control reservoir not present. As a result, the relay valve'section functions to release pressureirom the lbrake cylinder more gradually, because the piston 45 moves slowly downwardly to only partially, or crack, open the exhaust passages 54. As the rate of retardation diminishes due to this release of pressure from the brake cylinders, the pendulumV |66 swings back to the right until contact |68 disengages from contact |1I. Each release valve |43 will then be seated and theY parts of each control valve device will again assume lap position, .with the cut-off valve piston |21 remaining in lower position.

7 vAs the speed of the vehicle diminishes, the co- 2,055,106 vWhen fluid'underpressureis supplied to theV in the rate of retardation of the train will be small and a more uniform rate of retardation will be maintained. Y

YIf when the retardation controller contact |68 disengages from the contact I1 I, the release valve |43 should fail to be seated, then a total release of the brakes would result were it not for the limiting valve |49. When the pressure acting on valve |49 from passage |48 falls below a predetermined value, corresponding to the upward force exerted by spring |50, the limiting valve |49 will be seated, and sufficient pressure is thereby maintained in the volume below relay piston 45 to insure that the train will be brought to a stop.

When it is desired to effect a release of the brakes following a service application, the brake valve device is operated to Release position, whereupon the self-lapping magnet Valve winding 4Gillis deenergized and a total release of fluid pressure from the brake cylinder is effected.

If at the time the brake valve handle is moved to release position, the pneumatic cut-off valve piston |21 should be in its lowermost position, the operator may open switch |65 in the circuit to the retardation controller device and full control of the brakes will then be transferred to the brake Vvalve device I4.

Auxiliary service application In case of failure of the electropneumatic control in effecting an application by straight air operation, a service application by automatic operation may be effected by movement of the brake valve handle to Automatic service position. In this position, rotary valve |51 disconnects the brake pipe from the feed valve device I6I, and connects the brake pipe to the atmosphere through a port having a restriction |88 therein. The brake pipe is thus vented to the atmosphere at a service rate. Y

As before explained, a service rate of brake pipe reduction causes the automatic valve piston 88 in each control valve device to move to service position, to effect a supply of iiuid under pressure from the connected auxiliary reservoir IIO to the volume below relay piston 45, in accordance with the degree of brake pipe reduction. The flow from the auxiliary reservoir II!) is through pipe and passage I II, slide valve chamber 85, slide valve port II2, and from thence to both the volume reservoir 99 and the double check valve chamber I8 I. From the double check valve chamber I I, the flow is to the under side of relay piston 45 through the same passages as previously described for a straight airservice application.

After a predetermined pressure has been established in the volume below the relay piston 45, the inshot valve piston II9 operates as before to seat the ball valve II1.

n The volume reservoir 99 is provided to permit a more exible control of the pressure of fluid supplied to the volume below relay piston 45 through operation of the automatic valve section 22. If the volume reservoir 99 were not provided, the pressure effected below relay piston 45 would bear a relation to brake pipe pressure reduction much higher than in present standard equipments, and light applications of the brakes could not be effected. By introducing additional volume a given reduction in brake pipe pressure will effect a pressure below relay piston 45 more nearly in accordance with the ratio in standard automatic brake systems.

Now since the flow of fluid under pressure to the'under side of relay piston 45 passes through the pneumatic cut-off valve section 24 for either straight air operation or automatic operation, it follows that the retardation controller device I6 will function to control brake cylinder pressure for both modes of operation, and as described in connection with service `applications by straight air operation, Therefore, if the rate of retardation during automatic operation becomes great enough, the retardation controller device I6 will take control to limit the rate as already described.

When it is desired to effect a release of the brakes following an automatic application, the brake valve handle is moved to Release position, where the brake pipe is again connected to the feed valve device and brake pipe pressure restored. The automatic valve piston 88 is then actuated to lower position and slide valve cavity-94 connects the volume below relay piston andvolume reservoir 99 to passage 95 and pipe 96 leading to the atmosphere.

At the same time, port |03 in slide valve 86 registers with passage |04, so that the now higher brake pipe pressure unseats the fast recharge valve |06, and fluid under pressure flows past 'this unseated valve through passage |04 and port |63 to slide valve chamber 85, from whence it flows to the auxiliary reservoir |-|0. The auxiliary reservoir is thus recharged at a rapid rate, and when the pressure in the reservoir reaches a predetermined value, the fast recharge valve |06 seats, and further charging of the auxiliary reservoir takes place through the charging groove |11.

Emergency application When it is desired to effect an emergency application of the brakes, the lbrake valve handle is moved to the position indicated as Emergency. In this position, full strength current will bersupplied to each self-lapping magnet valve winding 64, and the brake pipe will be vented to the atmosphere through an unrestricted port |82 in the rotary'valve |16.

Each self-lapping magnet valve device will operate to supply fluid under pressure to the under side of each relay piston 45 to a maximum degree.

`At the same time, the emergency reduction in brake pipe pressure will cause each automatic valve piston 88 to move to emergency position, to also supply fluid under pressure from each auxiliary reservoir IS to the under side of each relay piston 45 to a maximum degree. Since the flow from the self-lapping valve section and from the automatic Valve section are both to the double check valve chamber lill, it will be obvious that only the supply which dominates in pressure will reach the relay valve section.

Thus during an emergency application, a double supply of fluid under pressure to operate each relay valve section is available, thereby ensuring that fluid under pressure will be supplied to the brake cylinders to a maximum degree. It will be noted however, that in both straight air and automatic applications fluid under pressure is supplied to the brake cylinders from the supply reservoirs 3B only.

During an emergency application, each inshot valve section will function as Vheretofore described, and likewise, the retardation controller device I6 will also function to limit the maximum rate of retardation.

When it is desired to effect a release of the brakes following an emergency application, the brake valve device is moved to Release position,

where, as' before described, each winding 64 is deenergized and each automatic valvepiston 88 is actuated to lower position.

While the' operation of the embodiment illustrated has been described in connection with operation from one end only, it will be quite apparent that another brake valve device |4`may be provided at the rear end of the train and similar connections made as for the brake valve device at the head end of the train, so that if it is desired to operate the train in either direction, control from either end may be effected.

While I have illustrated and described one particular embodiment of my invention, Vit will be quite apparent to those skilled in the art that many changes therein and modifications thereof may be made, and I do not wish to be limited to the specic embodiment shown, or otherwise than by the spirit and scope of the appended claims.

I-Iaving now described my invention, what I claim as new and desire to secure by Letters `Patent, is:

1. In a vehicle or train braking system, th combination with a brake cylinder and a reservoir, of a valve device operated upon an increase in pressure for effecting a supply of fluid under pressure from said reservoir to said brake cylinder, an electrically operated valve device for controlling a communication through whichluid under pressure is supplied to operate said first valve device, an automatic'valve device for controlling a second communication through which fluid under pressure is also supplied to effect operation of said first valve device, a fluid pressure operated cut-off valve device'for controlling the supply of fluid under vpressure through both of saidV communications, a retardation controller device, and means controlled by said retardation controller device for controlling'said cut-off valve device. f

2. In a train braking system,'the `combination with a brake cylinder, of a pressure operated valve device for controlling the supply of fluid under pressure to said brake cylinder, a reservoir, means Vestablishing a communication`- having'parallel branch` paths between said reservoir and said pressure operated valve device, an electrically controlled valve device for controlling the supply of fluid under pressure through said communication, al valve device inone of said branch paths operated upon af predetermined pressurefor closing said path, and Va second valve device in said other branch path operable by brake cylinder pressure for closing said other branch path, d

r3. In a vehicle brake system, the combination with a brake cylinder, of a pressure operated valve device for controlling the supply of fluid under pressure to said brake cylinder, means establishing a communication havingv parallel branch paths to said pressure operatedvalve device, an electricallyV controlled valve device Vfor controlling 'the supply of iluid'under pressure through said communication, a normally open valve device in one of said paths and operated at a predetermined pressure toclose said path, a reservoir, and a second valve device in the other of said branch paths and operable to close said path and to connect said reservoir to said pressure operated valve device. f d

4. In a train brake system, the combination with a brake cylinder, of a relay valvedevice for controlling the supply of uid under pressure to and its release from said brake cylindenmeans for effecting a supply of fluid under pressureV to said relay device to effect operation thereof, an

electrically operated release valve device operable to effect a release of iiuid pressure from said relay valve device, a control reservoir, and means normally isolating said reservoir and operable to connect said reservoir to said relay valve device before said release valve device is operated to release iiuid pressure therefrom.

5. In 'a train brake system, in combination, a brake cylinder, a valve device operated by the supply of uid under pressure thereto for controlling the supply of fluid under pressure to and its release from said brake cylinder, means for establishing a communication throughv which fluid under pressure is,` supplied to operate said valve device, a second valve device controlling said communication, said second valve device having a piston subject on both sides to brake cylinder pressure, an electrically operated valve device lfor reducing the pressure on one side of said piston, and a retardation controller device for controlling said electrically operated valve device.

6. In a train brake system, in combination, a brake cylinder, a relay valve device operated according to the supply of liuid under pressure thereto for controlling the supply of iiuid under pressure to and its release from said brake cylinder, means for establishing a communication through which iiuid under pressure is supplied to operate said relay valve device, a cut-olf valve device having a piston normally subject on both sides to brake cylinder pressure and operable when the pressure on one side of said piston is reduced to close said communication, an electrically operated valve device operableto reduce the pressure on one sideof said piston, an electrically operated release Valve device operable to diminish the pressure of fluid supplied to operate said relay valve device, and a retardation controller device for controlling operation of said electrically operated valve device.

7. In a train brake system, in combination, a brake cylinder, a relay valve device operated according to the supply of fluid under pressure thereto for controlling the supply of fluid under pressure to and its release from said brake cylinder, means for establishing a communication through which fluid under pressure is supplied to operate said relay valve device, a reservoir, a second valve device controlling said communication to said relay valve device and having a piston normally subject on both sides to brake cylinder pressure, a magnet valve device operable when energized to reduce the pressure on one side of said piston, said second valve device being operable thereupon to cut oi said communication to said relay valve device and to connect said reservoir to said relay valve device, and a retardation controller device for controlling said magnet valve device. Y

8. In a train brake system, in combination, a brake cylinder, a relay valve device operated according to the supply of fluid under pressure thereto for controlling the supply of fluid under pressure to and its release Vfrom said brake cylinder, means for eiecting a supplyV of fluid under pressure to said relay valve device, a release valve device operable to release fluid pressure from said relay valve device, a control reservoir normally charged to brake cylinder pressure, a retardation controller device for controlling said release valve device, and means controlled Vby said retardation controller device for connecting said control reservoir to said relay valve device before said release magnet valve device is operated to release uid pressure from .said relay valve device.

9. In a train brake system, in combination, a brake cylinder, a relay valve device for controlling the supply of fluid under pressure to and its release from said brake cylinder, means for effecting a supply of fluid under pressure to operate said relay valve device, a valve device having a piston normally subject on both sides to brake cylinder pressure for controlling said last supply, electroresponsive means for diminishing the pressure on one side of said piston to cause said valve device to cut ofi said supply, a second electroresponsive means operable to reduce the pressure of said supply to said relay valve device, a. retardation controller device Vcontrolling said two electroresponsive means, and a limiting valve device operable to limit said reduction of pressure.

10. In a train brake system, the combination with a brake cylinder, of a relay valve device having a piston operated upon an increase of pressure on one side thereof to effect a supply of fiuid under pressure to said brake cylinder and operated upon a reduction in pressure on said side for effecting a release of pressure from said brake cylinder, means for eiecting a supply of fluid under pressure to one side of said piston, means for reducing the pressure of fluid supplied to said side of said piston, a reservoir normally charged to brake cylinder pressure, and means operable to connect said reservoir to said side of said piston when said releasing means is operated to reduce the pressure on that side.

11. In a train brake system, the combination With a brake cylinder, of a relay valve device controlling the supply of fluid under pressure to and its release from said brake cylinder, said relay valve device being operated upon a supply of iluid under pressure thereto to eiect a supply of iiuid under pressure to said brake cylinder and being operated upon a reduction of the pressure of the supply to effect a release of pressure from said brake cylinder, a retardation controller device, means operated by said retardation controller device at one rate of retardation for reducing the pressure of fluid supplied to said relay valve device, and means operated by said retardation controller device at a lower rate of retardation for controlling the rate at which pressure is reduced in said relay valve device.

12. In a train brake system, the combination With a brake cylinder, of a relay valve device operable to control supply of fluid under pressure to and its release from said brake cylinder, said relay valve device being operated upon a supply of fluid under pressure thereto to effect a supply of liuid under pressure to said brake cylinder and operated upon a reduction in the pressure of iiuid supplied thereto for eiecting a release of pressure from said brake cylinder, a reservoir normally charged to brake cylinder pressure, a retardation controller device having two normally open contacts, means operated upon closing of one of said contacts for cutting off the supply to said relay valve device and for connecting said reservoir thereto, and means operated upon closing of said other contact for reducing the pressure of fluid supplied to said relay valve device.

13. In a train braking system, in combination, a brake cylinder, a relay valve device controlling the supply of fluid under pressure to and its release from said brake cylinder, means for establishing Ya communication having parallel branch paths through which uid under pressure is supplied to operate said relay valve device, an inshot valve device controlling one of said branch paths and operated upon a predetermined pressure to close said path, a cut-01T valve device having a piston normally subject on both sides to equalized pressures and operated upon a reduction in pressure on one side for closing said other branch path, a selective valve device controlling the supply of fluid under pressure through said communication, said selective valve device having a chamber to which fluid under pressure may be supplied from a plurality of sources, means for electro-pneumatically eiecting a supply of fluid under pressure to said chamber, a brake pipe, means operated upon a reduction in brake pipe pressure for effecting a supply of fluid under pressure to said chamber, and a brake valve device operable to control said electropneumatic means and operable to elect reductions in brake pipe pressure.

14. A control valve device having an electrically controlled self-lapping section, a relay valve section, an automatic valve section, an inshot valve section and a iluid pressure operated cut-off valve section, said relay valve section being operable to control a ilow of fluid under pressure supplied to eiect an application of the brakes,Y said self-lapping and automatic valve sections being operable to control a communication having branch paths leading from said twosections to said relay valve section, said inshot valve section being operable to control one of said branch paths, and said fluid pressure operated cut-off valve section being operable to control the other of said branch paths.

15. A control Valve device having an electrically controlled self-lapping section, a relay valve section, a triple valve section, an inshot valve section, a fluid pressure operated cut-off valve section, and a double check valve, said relay valve section being operable to control the ow of iluid under pressure supplied to effect an application of the brakes, said self-lapping and triple valve sections being operable to eiect separably or concurrently a different supply of fluid under pressure to said relay valve section through a communication having parallel branch paths, said double check valve being operable to select between said two supplies, said inshot valve section controlling one of said branch paths, and said uid pressure operated cut-oir valve section controlling the other of said branch paths.

16. A control valve device having an electrically controlled self-lapping section, a relay valve section, an automatic valve section, an inshot valve section, a cut-off valve section, a magnet valve section, and a limiting valve, said control valve device having a communication with two branch paths leading from said self-lapping and automatic valve sections to said relay valve section, said inshot valve section controlling one of said branch paths and said cut-01T valve section controlling the other of said branch paths, said magnet valve section controlling operation of said cut-off valve section and being also operable to release fluid pressure from said relay valve section, and said limiting valve being operable to prevent release of pressure from said relay valve section by said magnet valve section below a predetermined value.

17. In a vehicle brake system, in combination, a brake cylinder, means for eiecting a supply of uid under pressure to said brake cylinder, means operated according to the rate of retardation of the vehicle, and means responsive to operation of said last means at a chosen rate of retardation for eiecting a release of fluid under pressure from said brake cylinder and for controlling the rate of release according to the existing brake cylinder pressure.

ELLIS E. HEWITT. 

